Electrical connector assembly

ABSTRACT

Connector housings (11, 12) to be mounted on a printed circuit board (100) have a plurality of rows of contacts (13, 14) extending from wall surfaces of the housing (11, 12). These contacts (13, 14) are soldered to conductive pads (23) of a flexible circuit (20). The flexible circuit (20), bent in a generally U-shaped, about an insertion portion (31) of a metallic guide portion (30) which is to be inserted between rows of contacts (50) of a mating connector (40) for interconnection therebetween. The guide member (30) preferably engages a ground conductor (176) on the reverse surface of the flexible substrate and includes extending portions (142) to groundingly engage conductive member (43, 124) positioned at both ends of the housing. In an alternate embodiment strengthening plates may be adhered to the flexible circuit between the opposed arrays of conductive pads and ground contact pads.

FIELD OF THE INVENTION

The present invention relates to an electrical connector, morespecifically to a high density electrical connector such as a PC cardconnector that uses a flexible circuit for interconnecting the contactof the PC connector to another connector mounted on a circuit hoard.

BACKGROUND OF THE INVENTION

Advances in electronic devices including microprocessors have created alarge market for compact electronic apparatus using memory or PC cards,hard disk drives (HDDs), etc. A docking connector or a memory cardconnector is used in such electronic apparati. The docking connector isused to interconnect another similar electronic apparatus for creating anetwork and also to connect peripheral equipment such as a submemoryapparatus. A memory card connector receives one or more memory card oran HDD for electrical connection thereto.

Recently, needs have arisen for card type devices known a PC cards forexpansion or additional performance of compact electronic equipment suchas notebook personal computers. Such PC cards are normally received in aPC card connector installed in a compact electronic equipment to provideadded memory capacity or interfacing with external devices such asperipheral equipment. Typically, PC card connectors have dual stackedconnector mating portions to permit reception of three types of PCcards, i.e., Type I, Type II and Type III.

These docking connectors and PC or memory card connectors include aplurality of contacts often more than one hundred disposed in a matrixhaving a plurality of rows. Such contacts are bent at right angles or inan L-shape with respect to the connector and are soldered to respectiveconductive paths or traces on a main PC board. One example of suchmemory card connector is disclosed in U.S. Pat. No. 5,324,204. In thisparticular example, four rows of contacts are bent in a staggeredrelationship to be connected to the main PC board in eight rows.

Typical examples of such connectors also are disclosed in JapanesePatent Publication, No. 6-332573 and Japanese UM Publication No.6-56992. The former connector has contacts aligned in a connectorhousing and bent at substantially right angles at the rear position tobe connected to a rain circuit board. In the latter connector, contactsof dual stacked connectors extend at their rear positions toward eachother, i.e., toward the center position to be connected to an auxiliarycircuit board at the center position, thereby interconnecting theauxiliary and main circuit boards by the board-to-board connector.

Unfortunately, as electronic equipment becomes more compact, a higherdensity of contacts is required. The individual contacts, therefore,have smaller dimensions and pitch, which makes it difficult to formreliable connections with a main circuit board using a connector havingrelatively long solder tines of the contacts of the former connector.Although the latter connector is effective to realize relatively finepitch connections, the connector requires a larger number of components,thus making it more difficult to manufacture and more expensive.

Moreover, a standard to form signal and ground (SG) of PC cardconnectors has been added recently. One object is to isolate signals tobe transmitted through one connector from those transmitted throughanother connector, thereby preventing noise due to cross talk.Unfortunately, however, such noise protection is not always sufficientin conventional connectors.

Additionally, in the above conventional connectors, the connection ormounting location of the connector or its contacts on a main circuitboard is required to be predetermined, thereby restricting the design ofthe main circuit board and precise manufacture of conductive throughhole patterns, etc. with small tolerances. It is, therefore, desirableto provide flexibility in connection or mounting.

Using a flexible circuit (FC) for interconnecting circuits on asubstrate such as a small-size printed circuit board (PCB) andhigh-density-mounted electronic equipment is known in the art. Such anelectrical connector for an FC generally comprises a plurality ofcontacts to be engaged with conductive pads formed on the FC, a housingfor disposing and holding the contacts, and a movable plastic cover orother member for pushing the FC into the housing and the conductive padsformed thereon into positive engagement with the contacts in thehousing. Examples of conventional electrical connectors for FC aredisclosed in a Japanese Patent Publication No. 61-131382, a Japanese UMPublication No. 2-120780, and a Japanese Patent Publication No.5-251140.

U.S. Pat. No. 3,923,364 discloses an electrical connector assemblyincluding a housing having a plurality of contacts disposed along anelongate opening; a shielded flexible substrate having a widthcorresponding to the opening of the housing and conductive signal tracesand pads and ground conductive pads on one surface thereof correspondingto the contacts in the housing; and a guide member having a plateportion to be disposed in a flexible substrate bent in a generallyU-shape with the one surface outside to be inserted into the opening ofthe housing whereby, upon inserting the guide member and substrate intothe housing opening, the signal and ground pads on the one surface ofthe substrate are electrically engaged to corresponding contacts in thehousing.

As electronic equipment becomes smaller with a higher density ofcontacts, e.g., the pitch of the contacts is less than 0.5 mm, thedimensions of the contacts to be used therein will also become smallerand, therefore, be more easy to deform. It is very difficult toaccurately position the contacts, especially their solder-terminatingportions, in the desired location and to maintain them so as not todeform the contacts upon handing and mounting the connector on to thesubstrate.

Also, for the electrical connector utilizing the FC, it is difficult toprecisely and firmly urge the movable plastic cover to engage over thefull width of the FC with the plurality of contacts without having somedeformation over the full width of the FC. Accordingly, reliability ofconnection between the conductive pads and the contacts has beendecreased.

Therefore, an object of this invention is to provide a small and highdensity electrical connector assembly, that utilizes the FC and enablessimple structure and easy handling.

It is another object of this invention to provide an electricalconnector assembly having a ground function and permitting easy handlingin which the plurality of the conductive pads on the FC and the contactsin the housing are interconnected with high reliability.

It is yet another object of this invention to provide an electricalconnector assembly for card bus, which enables one or more memory cardconnector etc. to connect easily and reliably to the PC board.

In order to solve the problems of the prior art electrical connectorassembly and to achieve the above mentioned objects, the electricalconnector assembly of the present invention comprises a housing havingplural rows of contacts, a substrate, such as a flexible printed circuitboard (FC) to be connected to the contacts of the housing at both endsof the flexible printed circuit board, said printed circuit board havinga plurality of conductive traces and pads, and a guide member to beinserted in the FC, the guide member being bent in a generally U-shapeto force the FC between rows of contacts of a corresponding connector tointerconnect the conductive traces and contacts.

In accordance with one aspect of the present invention, the electricalconnector assembly includes a housing having a plurality of contactsdisposed along an elongate opening; a flexible substrate having a widthcorresponding to the opening of the housing and conductive traces on onesurface thereof corresponding to the contacts in the housing; and aguide member having a plate portion to be disposed in a flexiblesubstrate bent in a generally U-shape with the one surface outside to beinserted into the opening of the housing. The connector assembly ischaracterized in that: the housing includes a ground conductive memberat at least one end thereof; the flexible substrate is formed with aground conductor on the other surface thereof; and the guide member is aconductive member adapted to further provide a connection to ground forthe assembly whereby the contacts and the conductive traces areelectrically connected by the force exerted by the guide member on theflexible substrate and the ground conductor of the substrate isconnected to the ground conductive member of the housing by the guidemember.

In one embodiment of the invention using a flexible substrate havingconductive traces on one surface, the assembly further includesstrengthening plates disposed on the other surface of the substrate atthe locations corresponding to the conductive pads.

One aspect of the present invention is an FC having two arrays ofcorresponding conductive pads and conductive traces on one surface withthe plurality of conductive pads of the arrays arranged in rows in anopposed relationship. A plurality of openings are disposed between thearrays leaving narrow bridge portions between adjacent openings.Strengthening plates are attached to the reversed surface at thepositions corresponding to the conductive pads with portions of thestrengthening plates extending into the openings by a predeterminedlength.

Also, another aspect of the present invention is a flexible circuit (FC)comprising conductive traces on one surface of a central film, a groundlayer on the reverse surface, and cover layers disposed to cover theconductive traces and the ground layer. A plurality of openings areformed in the cover layers substantially in rows at selected locationsthat avoid the conductive traces.

The FC according to the present invention has openings in the directionof the width at substantially center position between the rows of theconductive pads. The openings define the relatively narrow bridgeportions of the FC. The FC has a pair of strengthening plates adhered toboth sides of the openings and at least one surface of the FC. The pairof strengthening plates have edges extending into the openings by adesired length from both sides thereof.

Additionally, the FC according to the present invention has a pluralityof recesses arranged substantially in rows near the bent portion. Therecesses are preferably formed by removing a part of one layer of amultiple-layer FC, thereby allowing the FC to bend smoothly at a desiredposition.

The FC is bent or folded along the bridge portions before being insertedinto a connector along with a guide member, and upon full insertion ofthe board and guide member, the conductive pads of the FC areelectrically connected with contacts in the connector. The edge portionsof the strengthening plates then abut the bottom in the housing forproper positioning of the FC in the connector, thereby assuring reliableelectrical connection between the conductive pads and the contacts.Also, it is bent at a desired angle, preferably a right angle along therecesses, thereby permitting connection to a connector such as the PCcard connector or other device at the edge portion. Since the electricalconnector assembly comprises a FC with no individual contacts bent atright angle with respect to a wall or L-shape as seen in the prior artelectrical connector assembly, the connector of the present inventioneliminates deformation of the guide between the contacts anddisengagement and short circuit caused therebetween. Accordingly, stableelectrical connections and easy handling are achieved. Also, thestructure having the FC connected to the contacts on the housing at theboth ends thereof enables high density.

According to another aspect of the present invention, the electricalconnector comprises a housing having two rows of contacts alone anelongate opening, a flexible printed circuit board having a plurality ofconductive traces on a surface corresponding to these contacts, and aguide member having a generally planer portion to be inserted into aU-shaped bent portion of the flexible printed circuit board, wherein theconductive traces on the flexible printed circuit board are forcedbetween the rows of the contacts by means of the guide member forestablishing electrical interconnection between the conductive tracesand the contacts in the housing, thus electrically connecting thecontacts with corresponding contacts of at least one electricalconnector terminated to the ends of the FC.

According to the electrical connector assembly, it is possible toconnect the high frequency signals to the contacts through theconductive traces on the surface of the FC. The FC is bent in a U-shapeto envelope the guide such that the guide electrically engages theground conductor of the FC board and upon inserting the FC into thehousing, the guide electrically engages the ground conductive members ofthe housing. Since all the conductive traces formed on the one surfaceof the FC can be signal traces, a high density and high frequencyelectrical connector is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example withreference to the accompanying drawings.

FIG. 1 is an isometric view of an electrical connector assemblyaccording to a preferred embodiment of the present invention.

FIG. 2A is a side view of the electrical connector assembly shown inFIG. 1 prior to mating with the corresponding connector.

FIG. 2B is a side view of the electrical connector assembly shown inFIG. 1 at a starting time for mating with the corresponding connector.

FIG. 2C is a side view of the electrical connector assembly fullycoupled with the corresponding connector.

FIG. 3 is a cross-sectional side view where the electrical connectorassembly according to the present invention is adapted to a stackedmemory card connector.

FIG. 4 is a partial model view of another embodiment of the electricalconnector assembly according to the present invention.

FIG. 5 is an isometric view of the electrical connector assembly ofanother embodiment according to the present invention.

FIG. 6 is an isometric view showing a situation where the guide memberin the electrical connector assembly shown in FIG. 5 is mounted in aflexible printed circuit board connected to the memory card connector.

FIG. 7A shows a front view of the housing of the electrical connectorassembly of FIG. 5.

FIG. 7B shows a side view of the housing of the electrical connectorassembly of FIG. 5.

FIG. 7C shows a cross-sectional view taken along the line 7C--7C of FIG.7A.

FIG. 8A is a plan view of the housing of FIG. 7A.

FIG. 8B is a bottom view of the housing of FIG. 7A;

FIG. 9A is a front view of a guide member of the electrical connectorassembly shown in FIG. 5.

FIG. 9B is a plan view of a guide member of the electrical connectorassembly shown in FIG. 5.

FIG. 9C is a rear view of a guide member of the electrical connectorassembly shown in FIG. 5.

FIG. 10A is a cross-sectional view of the guide member of FIG. 9 takenalong the line 10A--10A of FIG. 9A.

FIG. 10B is an end view of the guide member of FIG. 9A-C.

FIG. 11A is a front view of a flexible circuit inserted in an electricalconnector assembly.

FIG. 11B is a side view of the flexible circuit inserted in theelectrical connector assembly of FIG. 11A.

FIG. 12A is a cross-sectional view showing a guide member of theelectrical connector assembly disposed between the U-shaped flexiblecircuit prior to inserting the flexible circuit into a connectorhousing.

FIG. 12B is a cross-sectional view showing a guide member of theelectrical connector assembly disposed between the U-shaped flexiblecircuit with the U-shaped end of the flexible printed circuit boardinserted into the connector housing.

FIG. 12C is a cross-sectional view showing the flexible circuit securedby the guide member in the connector housing.

FIG. 13 is a plan view at one surface of the FC according to the presentinvention.

FIG. 14 is a bottom view of the reverse surface of the FC in FIG. 13.

FIG. 15 is a view similar to FIG. 14 prior to adhering the strengtheningplates.

FIG. 16 is a magnified cross-sectional view of the FC in FIG. 1.

FIG. 17 is a simplified cross-sectional view of the FC in FIG. 1 asinserted into a connector.

FIG. 18 is an isometric view of the FC in FIG. 13 showing how it isfolded or bent when inserted into a connector.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

FIG. 1 is an isometric view showing a major part of an embodiment of thepresent invention adapted to an electrical connector assembly, such as amemory card connector 10. FIGS. 2A through 2C show a process forinserting and connecting the memory card connector 10 of FIG. 1 to amating connector 40 disposed on and connected to a main substrate 100.That is, FIG. 2A shows a situation where the memory card connector 10and the mating connector 40 are separated from each other. FIG. 2B showsthe memory card connector 10 partially inserted in the mating connector40. FIG. 2C shows the memory card connector 10 fully mated with themating connector 40.

As appreciated from FIGS. 1 and 2, the memory card connector 10 of thespecific embodiment comprises two stacked connector housings 11, 12.Plural rows of contacts 13, 14 project from wall surfaces 11a, 12a ofthese housings 11, 12. In these Figures, the plurality of contacts 13,14 are two rows of signal contacts 13a, 14a and one row of groundcontacts 13b, 14b. As appreciated from the above mentioned U.S. Pat. No.5,324,204, these housings 11, 12 comprise, at front surfaces thereof, amemory card, or a plastic or a metallic plate holder for receiving theHDD (not shown in the FIGS. 1, and 2), respectively.

An FC 20 having sufficient length is connected to each contact 13, 14 ofthe connector housings 11, 12 at both ends 21, 22 of the conductivetraces of the FC 20 by means of solder etc. to conventional pads withthrough holes to form a card bus. A plurality of conductive traces 23having contact pads 24 are formed on an outer surface of the FC 20.

A guide member 30 is inserted into a middle portion of the FC 20 to bendit in a U-shape. The guide member 30 is preferably formed by stampingand bending a conductive metal plate in a traditional manner. As bestseen in FIG. 2A-2C, the guide member 30 has an insertion portion 31formed by folding the metal plate to be inserted between rows ofcontacts 50 of a mating connector 40 as hereinafter explained, and amactuation portion 32 generally perpendicular to the insertion portionand having a generally planer surface. The actuation portion 32 isprovided with a slot 33, having a width corresponding to the FC 20, forreceiving side edges thereof. The FC 20 is inserted in the slot 33 witha generally U-shape along an outer surface of the insertion portion 31.

The receptacle type mating connector 40 has an elongate box-shapedhousing 41 to be mounted on the main substrate 100. The housing 41 hasan opening 42 at an upper surface thereof, and has a plurality ofsurface mounted type (SMT) contacts 50 disposed and secured at bothsides of the opening 42. The housing 41 has metal mounting fixtures 43at both ends in the longitudinal direction of the housing 41, andpreferably the connector housing 41 is soldered and secured on aconductive layer (not shown) on the main substrate 100.

Each of the contacts 50 of the connector 40 includes a resilient contactbeam 52 having a contact surface 51 near the front end thereof, amounting portion 53 to be inserted and secured in a contact receivingopening of the housing 41, and a connecting portion 54 to be surfacemounted to conductive pads 102 on the main substrate 100. Preferably, alength of the resilient contact beam 52 is selected in various differentlengths, and disposed in staggered relationship to achieve high densitydisposition. As seen from FIGS. 2A, the contact surf ace 51 of eachcontact 50 projects into the opening 42 of the housing 41.

In a condition in which the memory card connector 10 is not mated orconnected to the corresponding connector 40, that is, in the situationshown in FIG. 2A, the contact pad portion of the FC 20 is bent in agenerally U-shape. Accordingly, as shown in FIG. 2B, the U-shaped FC 20can be easily inserted into the housing 41 with low insertion force andessentially without engaging the contacts 50. Finally, as shown in FIG.2C, when the insertion portion 31 of the guide member 30 is insertedinto the opening 42 of the corresponding connector 40 the U-shapedportion of the FC 20 formed with contact pads 24 is forced outwardlyfrom inside to urge and expand outwardly the contact beams 52 of thecontacts 50. Therefore, the contact pads 24 of the FC 20 of theconductive traces 23 are forced and engaged with the contact surfaces 51of the contacts 50, thereby interconnecting the contacts 13, 14 of thememory card conductor 10 to the contacts 50 of the mating connector 40,further inter-connecting between pads 102 on the main substrate 100.

If the FC 20 is formed with a ground conductive layer on an innersurface thereof, the insertion portion 31 of the guide member 30 engagesthe conductive layer. Although it is not shown, the guide member 30 ispreferably engaged with the mounting metal fixture 43 of the housing 41at the both ends in the longitudinal direction of the guide member 30 toelectrically engage the ground conductive layer of the FC 20.

As is readily appreciated from a comparison between the connectors 10,40 of the FIGS. 2A through 2C and the conventional memory card connectordisclosed in the above described U.S. Pat. No. 5,324,204, the electricalconnector assembly of the present invention replaces the plurality ofL-shaped contacts disposed in staggered relationship of the prior artconnector with the FC 20 and the corresponding connector 40. Inaccordance with the connector of the present invention an easily handledand a highly sense arrangement corresponding to the conductive traces ofthe FC 20 is achieved because of elimination of plural rows of thedeformable and high density L-shaped contacts. Further, an importantmatter is that length of the-signal traces from contracts 13, 14 of thehousings 11, 12 to the contacts 50 of the mating connector 40 can beformed such that the length is essentially constant. Accordingly, sinceeven in high speed data signals it is possible to make signaltransmission time or signal delay constant, the present connector issuitable for a card bus for transmitting high speed and high frequencysignals. Further, since the memory card connector 10 is detachablyconnected to the connector 40 mounted on the main substrate, it shouldbe noted that the termination assembly of the connector andserviceability are substantially improved.

FIG. 3 is a cross-sectional view showing entire memory card connector10, of the present invention, including a memory card retention portion15. The memory card retention portion 15 of the memory card connector 10is formed by bending a thin metal sheet. In the preferred embodiment ofthe electrical connector assembly shown in FIG. 3, the connectorhousings 11, 12 are in a stacked arrangement with the respectivecontacts 13, 14 overlying each other. However, the present invention isnot limited to such an embodiment, for example, the present inventioncan be applied to a card bus for interconnecting contacts on wallsurfaces of a pair of housings disposed in opposite relationship.

Another such embodiment of an electrical connector 60 is show in FIG. 4.Electrical connector assembly 60 comprises a pair of separate dockingconnectors or memory card connectors 61, 62. Each of the connectors 61,62 opposes each other at a wall surface thereof and preferably includesplural rows of multiple number of contacts 63, 64, including signalcontacts 63a, 64a and ground contacts 63a, 64b. Between both connectors61, 62 is a mating connector 40' soldered on a main substrate 200. Themating connector 40' can be essentially similar to the mating connector40 shown in FIGS. 1 through 3. A FC 70 is connected to the contacts 63,64 at one end of the conductive traces thereof on the walls of the bothconnectors 61, 62 by means of a prior art technique. A middle portion ofthe FC 70 is inserted into a slot of a guide member 80. Contact pads(not shown) at the middle portion of the FC 70 are forced by the guidemember 80 into an opening of the connector 40' to engage contacts 50'disposed at both sides of the opening to establish interconnection.

With reference to FIGS. 5 through 12, another embodiment of anelectrical connector of the present invention will be described. FIG. 5is an isometric view of the electrical connector of the anotherembodiment. FIG. 6 is an isometric view in which the guide member to beused for the electrical connector is positioned on the FC that isconnected to the memory card connector. FIGS. 7A-C and 8A-B show ahousing of the electrical connector shown in FIG. 5. FIGS. 9A-C and10A-B show the guide member of the electrical connector shown in FIG. 5.

An electrical connector 110 is provided with a housing 120 having anopening 121 for receiving an FC 160, a plurality of contacts 122opposedly disposed in two rows in the housing 120, and a guide member140 for forcing and securing the FC 160 inserted into the housing 120.Plate-like ground conductive members 124 are provided on both endsurfaces 120a of the housing 120 by pressing side portions 124a intoslots 120b in the housings 120 to engage projections (not shown) formedat side portions 124a with the housing 120 as shown in FIG. 8B. When theguide member 140 is moved in the direction of arrow 141, as will bedescribed hereinafter, to be inserted into the housing 120, a groundportion 142 of the guide member 140 engages the projections 124b of theconductive ground members 124. As the conductive ground member 124 ismounted and connected on the substrate (not shown), the mountingstrength of the housing 120 to the substrate is enhanced. A plurality ofcontacts 122 disposed in the housing 120 are engaged, respectively, withthe conductive pads 164 of the signal traces 162 formed on the FC 160.

As shown in FIG. 6, the FC 160 is bent at a middle portion 165 and endportions 166, 168 of the FC 160 are connected to corresponding contactsof a memory card connector 180. A share of the FC 160 is schematicallyshown in FIGS. 11A-B and 12A-C. The FC 160 is continuously bent at themiddle portion 165 thereof to form two wiring portions or arrays 170,172. The wiring portions or arrays 170, 172 are formed with signaltraces 162 shown in FIG. 6 and conductive pads 164 on both surfaces170a, 172a of the wiring portions 170, 172. Also, the wiring portions170, 172 are formed with a ground conductor or ground wiring at backsurfaces 170b, 172b, respectively, such as described below withreference to FIGS. 13-18. The ground wiring or conductor preferably isformed on entire back surfaces 170b, 172b or, alternatively, may beformed only on a portion thereof.

The guide member 140, as shown in FIGS. 9A-C and 10A-B is, for example,integrally formed by stamping and bending a sheet of metal made ofcopper alloy such as phosphorous copper, and is formed with the abovedescribed ground portions 142 at both end portions of the guide member140. Upon forming the guide member 140, the stamped metallic sheet isbent at the middle portior 140a and is outwardly bent at the endportions. The end portions are bent downwardly to form the groundportions 142. The ground portions 142 have resiliency, thereby grippingthe housing 120 from both sides when assembled thereto. The guide member140 is disposed between the wiring portions or arrays 170, 172. Untilthe guide member 140 is inserted into the housing 120, the guide member140 is preengaged with projections 191 (see FIGS. 11 and 14) formed onthe FC 160.

Now, with reference to FIGS. 11A-B and 12A-C, a sequence will bedescribed in which the FC 160 is inserted into the housing 120 and issecured by means of the guide member 140. In order to secure the FC 160in the housing 120 by the guide member 140, first, as shown in FIG. 12A,the guide member 140 is disposed at a position spaced apart from themiddle portion 165 of the FC 160. Then, as shown in FIGS. 11A-B and 12B,the middle portion 165 of the FC 160 is inserted into the housing 120.After inserting the middle portion 165 of the FC 160 into the housing120, as shown in FIG. 12C, the guide member 140 rides over theprojections 161 of the FC 160 to be inserted into the housing 120, andthe middle portion 165 of the FC 160 inserted into the housing 120 andis forced into position by the guide member 140. Accordingly, the groundwiring formed on the back surfaces 170b, 172b of the FC 160 arepositively engaged with the guide member 140, and, additionally theground portions 142 of the guide member 140 engage the projections 124bof the ground conductive member 124, as described above. The guidemember 140 is made of metal, thereby eliminating deformation or breakingof the guide member when the guide member 140 is inserted into thehousing 120. Accordingly, the conductive pads 164 (see FIG. 6) can bereadily and firmly engaged with the contacts 122 more easily than can aplastic cover or guide member, thus enabling excellent reliability andeasy operation. Further, in the situation in which the metallic guidemember 140 is inserted into the housing 120, the guide member 140engages both the ground conductive members 124 secured in the housing120 and the ground conductor or wiring (not shown) on the FC 160, theguide member 140 also functions as a around member.

A preferred embodiment of the FC 160 in accordance with the presentinvention is illustrated in FIGS. 13 through 16. FIG. 13 shows onesurface 160a of the FC 160 while FIG. 14 shows the reverse surface 160bthereof. Also shown in FIG. 15 is the surface 150b before adheringstrengthening plates 190, 196, which will be described hereinafter.Furthermore, FIG. 16 shows an enlarged cross-sectional view in thethickness direction from the slat to the edge portion.

As shown in FIG. 16, the FC 160 is formed as a multi-layer structure. Acentral film 182 of polyamide or the like separates one side structure182a to form the surface 160 and a reverse side structure 182b to formthe surface 160b. Each structure 182a, 182b, is made by an electricallyconductive film of copper or the like and a cover layer 185 of polyamideor the like adhered on the surface of the central film 182 by adhesivematerial 183a, 183b. The electrically conductive film is further etchedto form conductive patterns 162 and a ground layer 176, which will bedescribed hereinafter.

As shown in FIGS. 13 and 16, the structure 182a on surface 160a of thePC comprises conductive arrays 170, 172, having conductive pads 164,including conductive traces 162, connection portions 167 connected toconductive traces 162, and through-holes 169 extending to the othersurface 160b. Each conductive trace 162 interconnects the respectiveconductive pads 164 and connection portion 167. As best shown in FIG.16, the conductive pads 164 have a gold or solder plating layer 163. Thepads 164 are arranged in corresponding positions to the connectorcontacts, such as in connector 110 shown in FIGS. 5-12, to receive theFC 160 and are staggered in the particular embodiment shown in FIG. 13.Note that ground contact pads 174 are mixed in the rows of theconductive pads 164 as shown in FIG. 13. The ground contact pads 174 aredisposed at locations to engage with desired contacts in the connector.Also, the ground contact pads 174 are electrically connected to a groundlayer 176 to be described hereinafter by way of via holes 173 extendingin the direction of the thickness of the FC. The connection portions 167formed at the edge portions of the FC 160 are in a ring form to besoldered to the contacts of a PC card connector and are formed withthrough-holes 169 as mentioned above.

The structure 182a on surface 160a also includes a plurality of recesses184 that extend into the cover layer 185 and are formed by partlyremoving the cover layer 185 and are arranged substantially in rows, asseen in FIGS. 13 and 18.

The FC 160 is preferably formed with openings or slots 186 extendingtherethrough and at substantially center position between the rows ofthe conductive pads 164. The openings 186 provide the FC 160 withrelatively narrow bridge or belt-like portions 188 therebetween.

As best shown in FIGS. 14 through 16, the reverse structure 182b onsurface 160b includes the ground layer 176 and connection portions 178.The ground layer 176 includes a plate portion 175 and mesh portions 177.The plate portion 175 comprises an electrically conductive film ofcopper or the like extending in two dimensions while the mesh portions177 are formed by etching the electrically conductive film in a slantedmesh as shown in FIG. 14 through 15. Also, the ground layer 176 extendsfrom the edges of the meshed portions 177 to the edges of the FC 160 forconnection to the connection portions 178 that are substantially similarconfiguration as the above mentioned connection portions 167. Theconnection portions 178 receive ground connection terminals of the PCcard connector at the through-holes 179 extruding to the surface 160afor making solder connections to contacts of a connector (not shown).

The FC 160 further includes first and second plastic strengtheningplates 190, 196 made from glass-filled epoxy resin or the like that areadhered on the surface 160b as shown in FIG. 14. The first strengtheningplates 190 are positioned at both sides of the openings 186 as a pairand at the immediate reverse side of the conductive pads 164. Note thatthe first strengthening plates 190 include opposed edges 192, 193 withedge 192 having projections 191 that extend into the openings 186 whenthe first strengthening plates 190 are adhered. The edges 192 areparallel with the openings 186. As shown in FIGS. 14 and 15, the firststrengthening plates 190 substantially cover the plate portion 175.Also, at least one of the pair of the first strengthening plates 190 isformed with engaging slots 194 or projections 191 to be used preliminaryfor retaining the FC 160 to guide member 140 when it is inserted intothe connector, as previously described with reference to FIG. 11.

Additionally, the second strengthening plate 196 is adhesively securedat the locations of the connection portions 167, 178 using adhesivematerial 183b such as a liquid solder resist. This makes it easy tosolder the connector to the PC card connectors. The second strengtheningplate 196 has through-holes at location corresponding to the connectionportions 167, 178.

A cross-sectional view of the FC 160 according to the present inventionas inserted into the connector 110 having a FC receiving opening 121 isshown in FIG. 17. The FC 160 is folded at the bridge portions 188 withthe conductive pads 164 facing outwardly.

A guide member or guide member 140 is used to insert the FC 160 into theFC receiving slot 121. As shown in FIG. 18, the FC 160 is bent at asubstantially rivet angle along the recesses 184 and the reverse surface160b near the edges 193 of the first strengthening plates 190. In theinserted portion, the edges 193 of the first strengthening plates 190abut against the bottom surface 123 of the FC receiving opening 121.This provides precise alignment of the conductive pads 164 with contactpoints of contacts (not shown) in the connector 110, thereby assuringreliable interconnection therebetween.

It is to be understood that the shown in FIGS. 1 through 4 may bemodified to include the support plates 190, as shown in FIG. 18 andadditional plates 196 (not shown). The support of reinforcing plates 190protects the inner surface of the FC.

While a plurality of exemplary embodiments of the electrical connectorassembly according to the present invention has been described herein,it is not intended that this invention be limited to the embodiments. Itwill be appreciated by those skilled in the art that variousmodifications can be made for specific applications without departingfrom the scope and spirit of the invention. For example, the recesses184 may not be limited to the particular shape but may have aconstricted portion along the outer periphery or may have widerportions. The strengthening plates 190 nay not be limited to plasticmaterial but may be replaced by metal plates.

The electrical connector assembly according to the present invention, asappreciated from the above description, provides following variousexcellent advantages. It is suitable for an application in which an highdensity electrical connector such as an memory card connector having aplurality of contacts is interconnected to corresponding conductiveareas on the printed circuit board. By using the flexible substrate, theright angle contact legs can be eliminated, thus enabling the highdensity contacts of the connector to be reliably and easilyinterconnected to the PC board conductive areas without having theproblems associated with deformation of the contact legs.

A high density electrical connector assembly is achieved, since theconductive traces or the conductive pads formed at the middle portion ofthe FC are engaged with a plurality of contacts in one connector and theother ends of the traces are connected to corresponding contacts of atleast one conventional FC connector terminated at the ends of the FC.

The electrical connection between the conductive pads and the contactsare established by inserting the guide member into the FC bent in agenerally U-shape. Since the guide member is forced between the rows ofthe contacts, an assured interconnection is provided even for an the FChaving sufficiently large width. Further, if a conductive metal guidemember is used for the FC having a ground conductor on the reverse sidethereof the guide member can be electrically engaged to groundconductive members at one or both ends of the housing. Thus a highdensity connector assembly for high frequency signals is obtained.

The flexible circuit according to the present invention assures highlyreliable electrical connection while maintaining a relatively narrowpitch between contacts by folding it along the relatively narrow bridgeportions and by the provision of the strengthening plates abuttingagainst the housing for accurate alignment or registration between theconductive pads and the contacts. Especially, the bridge portions arerelatively narrow to permit smooth folding of the FC, thus avoidingundesirable force being applied to the arrays of the conductors thereon.

Furthermore, the provision of the ground layer on the inner surface ofthe FC and the conductive patterns for transmitting signals on the outersurface effectively reduces crosstalk noise between the conductivepatterns.

Additionally, the recesses formed by removing a part of the layers nearthe bending positions of the FC permit bending of the FC at a desiredposition and angle.

We claim:
 1. An electrical connector assembly including a housing havinga plurality of contacts disposed along an elongate opening; a flexiblesubstrate having a width corresponding to the length of the opening ofthe housing, and having conductive traces on one surface thereofcorresponding to the contacts in the housing; and a guide member havinga plate portion to be disposed in the flexible substrate which is bentin a generally U-shaped about the plate portion with the one surfaceoutside, and to be inserted into the opening of the housing, theconnector assembly being characterized in that:the housing includes aground conductive member at least at one end thereof; the flexiblesubstrate is formed with a ground conductor on the other surfacethereof; and the guide member is a conductive member adapted to furtherprovide a connection to ground for the assembly whereby the contacts andthe conductive traces are electrically connected by force exerted by theguide member on the flexible substrate and the ground conductor of thesubstrate is connected to the ground conductive member of the housing bythe guide member.
 2. The electrical connector assembly of claim 1wherein the flexible substrate further includes strengthening platesdisposed on the other surface thereof at the locations corresponding tothe conductive pads.
 3. The electrical connector assembly of claim 1wherein the flexible substrate further includes a plurality of openingsformed between the arrays of conductive pads to define relatively narrowbridge portions; and parts of strengthening plate extend into theopenings by a predetermined length.
 4. The electrical connector assemblyof claim 1 wherein the flexible substrate further includes a cover layerdisposed over the conductive traces with conductive pads of the tracesbeing free of the cover layer to enable electrical connection thereto,the cover including a plurality of recesses formed substantially in aline thereon at locations where the conductive traces and conductivepads are not formed to facilitate bending of the flexible circuit at aselected location.
 5. An electrical connector having a housing, aplurality of contacts exiting the housing at an end, and a flexiblesubstrate being electrically connected to the contacts, the connectorcomprising:a first set of contacts included in the plurality ofcontacts, a second set of contacts being adjacent the first set ofcontacts and also included in the plurality of contacts, the flexiblesubstrate being connected to the first and second sets of contacts toform a closed loop extending from the end of housing; and, a guidemember disposed within the closed loop of the flexible substrate.
 6. Theelectrical connector as recited in claim 5 wherein the flexiblesubstrate comprises an inner surface disposed inside the closed loop andan outer surface disposed opposite the inner surface.
 7. The electricalconnector as recited in claim 6 further comprising a ground planedisposed on the inner surface.
 8. The electrical connector as recited inclaim 5 wherein the guide member further comprises a pair of actuationportions extending beyond the closed loop.
 9. The electrical connectoras recited in claim 5 wherein the guide member further comprisespositioning means being engageable with the flexible substrate.
 10. Theelectrical connector as recited in claim 9 wherein the positioning meanscomprises a notch which receives an edge of the flexible substrate. 11.A card connector assembly comprising:a card connector for receiving acard device; a receptacle connector disposed at an angle to said cardconnector, and a flexible circuit substrate having a signal circuit onone major surface and a grounding plane on the other major surface, saidflexible substrate being soldered to said card connector at a rear sidethereof and adapted to be removably received into said receptacleconnector; where said flexible circuit substrate is bent at the rearside of said card connector such that at least a portion is angled by atleast 90 degrees, and extends rearward toward said receptacle connectorgenerally within a height range determined by a height dimension of saidcard connector, whereby said receptacle connector receives said flexiblecircuit at a position close to the height dimension center of said cardconnector.
 12. A card connector assembly of claim 11, wherein said cardconnector includes a plurality of post terminals projected rearward tobe soldered to said flexible circuit substrate.
 13. A card connectorassembly of claim 11, wherein said receptacle connector includes ametallic guide member for assuring electrical interconnection betweensaid receptacle connector and said flexible circuit substrate.